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IMPROVED PROCESS OF PRESERVING WOOD AND TIMBER.

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TO ALL WHOM IT MAY CONCERN:

Be it known that I, DANIEL R. PRINDLE, of East Bethany, in the county of Genesee, and mate of New York, have invented a new and improved Process for Preserving Wood and Timber; and I do hereby declare that the following is a full and exact description thereof.

The nature of my invention consists in applying coal tar, common tar, or equivalent substance, which will permanentlyprcserve the wood by the double means of first filling its pores, thereby preoccupying them against air and moisture, and then by covering its outer surface, thus excluding air and moisture, the application being in such a manner as first to expel the moisture in the wood and occupy its place, and then after a period of seasoning to coat the wood wholly or partially, all substantially as hereinafter setforth, as follows:

After preparing a suitable boiler or vessel to contain the wood or timber, or articles thereof, such as fence posts, stakes, railroad sleepers, trellis-work, &c., which vessel may be made of any material or form, and is best applied at or beneath the surface of the ground, the furnace being in the ground, thereby preventing setting fire to the contents, I place in it as much of the material to be heated, as desired, or as the vessel can hold.

The timber may be partially or well seasoned in the ordinary way before subjecting to my process, but the.

amount of previous seasoning is not of essential importance. The tar is placed in the. vessel in suiiicicnt quantity, at least after melting, to partially immerse each stick or article of the wood or timber. Heat is applied and kept up long enough for the liquid tar or its volatile ingredients to enter through the material, thereby first expelling the moisture gradually upward, and then taking its place in the pores of the wood. The pieces or articles are then taken out and allowed to season or shrink for awhile, according to the nature of the material and the purpose of its use. Then, just before using,'these articles are coated with the residuum of the tar used in the first part of the process, applied while hot, and then covered with sand or some equivalent fine body, sifted or blown on the tar before it cools or hardens. The tar residuum is conveniently applied over the vessel used in first seasoning and saturating the wood, so that the melting can be easily effected and the clrippings be caught and saved. This coating is not essential only on those portions exposed to the weather, and especially the parts which are from their structure most likely to absorb air and moisture, such as the ends of the wood, or, as with fence posts, those parts near the surface of the ground.

I do not claim the simple saturation of wood with tar or the coating of it therewith separately, the whole process, substantially as above set forth, being necessary to the complete success of my invention. And though the preservative qualities of the large amount of creosote and essential oils found in coal tar are peculiarly valuable in this process for this purpose, I do not confine myself strictly thereto, as other products of the like resinous and oily character may possess equivalent properties, though not in so high a degree.

What I claim as my invention, and desire to secure by Letters Patent, is

The application of coal tar, common tar, or equivalent substance, or the ingredients thereof to wood and timber successively, substantially as specified, as a new process of preserving the same.

The above specification ofmy improved process for preserving wood and timber signed by me this 26th day of December, 1866.

D. R. PRINDLE.

Witnesses:

J. S. Bnown, E. J. Bnowu. 

